Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Fatigue & fracture of engineering materials & structures
20 (1997), S. 0
ISSN:
1460-2695
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract— The fatigue behaviour of polyoxymethylene (POM) of different molar mass (6.1 × 104–1.5 × 105) was studied at stress levels from 35 to 50 MPa (about 55 and 75% of the yield strength, respectively). It was found that cyclic loadings promoted bond breaking of the polymeric chains which considerably reduced the molar mass both in the crack tip region of cracked specimens and in the bulk in the case of uncracked samples. This process probably included the formation of reactive radicals which subsequently favoured the formation of microvoids that weakened the material. The static fracture toughness of fatigued samples decreased on increasing the stress level, the process accelerating as the cyclic loads approached the yield strength. As a result of material modifications during the tests the low molar mass resins did not exhibit stable crack propagation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1460-2695.1997.tb00324.x
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